Low salinity the culprit?

MTsquared · Dec 10, 2020

Softhammer said:
Feed more. I would definitely not dose unless you are completely sure about what you are doing. Surf the threads here and you will find more horror stories of dosing crap. Get more fish and feed them. Way more satisfying than pouring in needless chemicals.

Thanks, I got the NO3 and PO4 for dosing however, I have reservations about dosing that stuff. I am going to try to up the feedings to the fish and the corals and see if that helps. Also, plan on doing smaller water changes ~10% instead of ~20-25% like I was doing. I do also plan to try to up the salinity to 1.025-1.026 or 1.027 as that is an easy variable to eliminate.

Crustaceon · Dec 10, 2020

MTsquared said:
So I am trying to pinpoint what’s going on with my SPS frags. Experienced reefer that recently (6mo ago) upgraded to a larger tank and decided to add SPS - previous tanks was primarily LPS and Zoas. I have purchased several SPS frags from varying places and they look great for a few days and then within a couple of weeks they basically bleach the skin melts off and they die. I have no idea what’s causing this as I test my water regularly and do weekly or bi-weekly water changes (DT is Waterbox 130.4, ~100g display and ~20g sump) I typically do a 20-25g water change. I tested my water yesterday and here is what my got:
Alk 7.8
Calcium 440
Mag 1320
Ph 8-8.2 (Apex)
Salinity 1.023
I am at a loss and confused as all the parameters look great with the exception of the salinity being a little low. Could this be causing my SPS issues? I have some easier SPS and some Acros and same results. Mixed reef and most everything else seems to be doing well. Thanks in advance or any guidance on what else to check/ look for.

“weekly or bi-weekly water changes (DT is Waterbox 130.4, ~100g display and ~20g sump) I typically do a 20-25g water change.”

Found it.

“Nitrate. .04
Phosphate. < .05”

These will cause bleaching and STN. RTN (from what it sounds like) is caused by rapid parameter swings.

I’m Batman · Dec 10, 2020

Softhammer said:
Feed more.

Never worked for me. Now the whole “get more fish and feed more,” yes that would be great, but now you’ve got to quarantine those fish, taking weeks vs upping Po4 with NeoPhos or other additive that has the same purpose. There’s worse things to dose - vibrant anyone?

MTsquared · Dec 11, 2020

Crustaceon said:
“weekly or bi-weekly water changes (DT is Waterbox 130.4, ~100g display and ~20g sump) I typically do a 20-25g water change.”

Found it.

“Nitrate. .04
Phosphate. < .05”

These will cause bleaching and STN. RTN (from what it sounds like) is caused by rapid parameter swings.

So you’re saying the water change is too much volume which is causing the parameter swings? The nitrate and phosphate numbers you quoted were parameters another member posted to aim for.

Crustaceon · Dec 11, 2020

MTsquared said:
So you’re saying the water change is too much volume which is causing the parameter swings? The nitrate and phosphate numbers you quoted were parameters another member posted to aim for.

From my experience anytime you go past 5% tank volume in a water change, you’re taking an ever increasing risk of not having that newly made salt water match closely enough to the display’s parameters to avoid having your tank’s inhabitants be shocked by the difference. Usually temperature is the culprit and that new water will typically be colder that the display. A simple fix is to use a heater in the new salt water and match it to your display’s temp. Second on the list is an alkalinity level that’s higher than what’s in the display. Lower alk, tends to be fine. This is why it’s better to do lots of small water changes throughout the week vs. one big one. Those smaller change volumes are far less likely to have a localized impact on the tank when it’s quickly added.

As far as nutrients go, it’s FAR safer to run elevated nutrients (5ppm+ nitrates and .04ppm + phosphates) than super low ones. While many reefers have great success with Ultra Low Nutrient Systems, it’s not a forgiving technique and in all honesty, I just don’t see a benefit to it. Not even from an algae control perspective. Unless I was target feeding my corals multiple times a day, there’s no way I’d consider running under 2ppm nitrates at a dkh above 7. That screams “burned tip city” to me.

Dr. Jim · Dec 11, 2020

Crustaceon said:
From my experience anytime you go past 5% tank volume in a water change, you’re taking an ever increasing risk of not having that newly made salt water match closely enough to the display’s parameters to avoid having your tank’s inhabitants be shocked by the difference. Usually temperature is the culprit and that new water will typically be colder that the display. A simple fix is to use a heater in the new salt water and match it to your display’s temp. Second on the list is an alkalinity level that’s higher than what’s in the display. Lower alk, tends to be fine. This is why it’s better to do lots of small water changes throughout the week vs. one big one. Those smaller change volumes are far less likely to have a localized impact on the tank when it’s quickly added.

You brought up something I've been debating for a while, which is:
What is more stressful (for SPS)? Small daily water changes or one large monthly change?

I just started daily AWC this past year. For the previous 50+ years of reef-keeping the frequency has varied but lets just say, "monthly." So is it better to stress corals just a little EVERY day or just stress them once a month (with a "bigger" stress). I'm starting to lean toward the latter. (There are plenty of successful reefers doing 25-30% changes once a month).

I know the real answer may be "it doesn't matter".....but between the two choices, one is probably optimal.

Crustaceon · Dec 11, 2020

Dr. Jim said:
You brought up something I've been debating for a while, which is:
What is more stressful (for SPS)? Small daily water changes or one large monthly change?

I just started daily AWC this past year. For the previous 50+ years of reef-keeping the frequency has varied but lets just say, "monthly." So is it better to stress corals just a little EVERY day or just stress them once a month (with a "bigger" stress). I'm starting to lean toward the latter. (There are plenty of successful reefers doing 25-30% changes once a month).

I know the real answer may be "it doesn't matter".....but between the two choices, one is probably optimal.

The larger water change will be more stressful as even acros are unlikely to notice 1-2% of total water volume being slightly different all of the sudden vs. 10% in one shot. The smaller changes also grant more “acclimation” time between that overall weekly parameter shift.